Scientists must be able to repeat an experiment and get very similar results; otherwise their conclusions will be questioned. If
the results of a repeated experiment are different from the original results, the results of the experiment
lack bias
are precise.
lack controls.
are flawed.

The gene that causes sickle-cell disease is present in a higher percentage of residents of sub-saharan africa than among those of african descent living in the united states. even though this gene causes sickle-cell disease, it also provides some protection from malaria, a serious disease that is widespread in sub-saharan africa but absent in the united states. discuss an evolutionary process that could account for the different percentages of the sickle-cell gene among residents of the two regions.

Which of these best describes wde by replicating the chromosomes c) the cytoplasm is divided between the two new daughter cells d) the nucleus opens to allow the chromosomes to enter the cytoplasm

14) whenever diploid populations are in hardy-weinberg equilibrium at a particular locus a) the allele's frequency should not change from one generation to the next, but its representation in homozygous and heterozygous genotypes may change. b) natural selection, gene flow, and genetic drift are acting equally to change an allele's frequency. c) this means that, at this locus, two alleles are present in equal proportions. d) the population itself is not evolving, but individuals within the population may be evolving.